Folding knife



FIG. 1 is a perspective view of the folding knife; FIG. 2 is a right-side elevational view of the folding knife; FIG. 3 is a left-side elevational view of the folding knife; FIG. 4 is a top plan view of the folding knife; FIG. 5 is a bottom view of the folding knife; FIG. 6 is a front elevational view of the folding knife; and, FIG. 7 is a back elevational view of the folding knife. 

The ornamental design for a folding knife, as shown and described. 